Telephone system.



H. G. WEBSTER.

TELEPHONE SYSTEM.

APPLICATION FILED MABJQ, 1909.

1 ,O23,900, Patented Apr. 23, 1912.

4 I v Q g COLUMBIA PLANDGRAPH (20., WASHINGTON. n. c.

. UNITED STATES PATENT OFFICE.

HARRY G. WEBSTER, OF CHICAGO, ILLINOIS, ASSIGNOR, BY MESNE ASSIGNMENTS,TO KELLOGG SWITCHBOARD & SUPPLY COMPANY, A CORPORATION OF ILLINOIS.

TELEPHONE SYSTEM.

Specification of Letters Patent.

Patented Apr. 23, 1912.

To all whom, it may concern:

Be it known that I, HARRY Gr. I/VnBsTnR, a citizen of the United States,residing in Chicago, county of Cook, and State of Illinois, haveinvented new and useful Improvements in Telephone Systems, of which thefollowing is a specification.

The present invention is concerned with that feature of telephonesystems which has to do with the application of ringing current to acalled telephone line. In systems employing this feature, the act ofconnecting to the called line so as to complete the connection betweenthe calling and called line is followed by the application of ringingcurrent to the called line, which is appliedeither continuously orintermittently until the called party responds to the call by removinghis receiver from its hook, whereupon the source of ringing current isdisconnected.

The principal object of my invention is to provide circuits andapparatus of this type which shall be simple, economical to manufacture,and eflicient in operation.

In carrying out my invention, I provide a ringing key or other devicefor applying ringing current to the circuit and arrange to normally lookit against operation and to retain it locked until the called line hasbeen connected to. This act of connection frees the key formanipulation, but as soon as it is thrown to its actuated position it isagain locked and so held until the called party responds to the call,whereupon the key is again released and restored to normal. I alsoprovide a novel arrangement of circuit connections and relays whichcooperate with the key structure in the connection and disconnection ofthe ringing source.

The complete nature of the invention will be more fully understood uponreference to the accompanying drawing, andthe patentable features willbe particularly pointed out in the appended claims.

In the said drawing, I have illustrated the simple circuits of a manualtelephone exchange, provided with party lines and employing ringingcircuits and apparatus constructed and arranged according to myinvention. The substations A and B have their circuits shown in full andare connected by line limbs 1 and 2 to the exchange, where they areprovided with multiple jack terminals 3, 4, which are adapted to beunited to the link-circuit G, whose strands 5, 6 terminate at the leftin the tip and sleeve contacts 7 and 8 of an answering plug, and at theright in similar contacts 9 and 10 of a calling plug. The strands areprovided with the usual condensers 11 and 12 which conductively dividethe circuit into an answering end and calling end. As will hereinaftermore fully appear, the novel ringing circuits are associated with thecall ing end of the link-circuit. Each substation is provided with theusual transmitter 13, receiver 14, switch-hook 15, call-bell 16,condenser 17, and induction coil 18. A normally closed path for ringingcurrent extends through the bell 16 and condenser 17 and the transmitter13 is included in 9. normally open path. Each line is shown providedwith four substations, in the one instance designated A, A, A A and inthe other B, B, B B At the exchange the line limb 1 is connected througha normally closed contact of cut-off relay 19, line relay 20, to thenegative pole of grounded battery 21, While the line limb 2 is connectedthrough other normally closed contacts of cut-ofi' relay 19 to thegrounded pole of said battery. Line relay 20 controls line lamp 22. Atthe answering end of the cord-circuit, sleeve supervisory relay 23 andtip supervisory relay 24 are connected in bridge of the strands 5 and 6with the battery 21 interposed. These relays jointly control theanswering supervisory lamp 25. This end of the link-circuit is alsoprovided with the listening key contacts 26, 27 and 28, which areadapted, when depressed, to connect the test relay 29 through conductor30 to the tip contact of the calling plug and to include the headreceiver 31, condenser 32, and secondary of induction coil 33 in bridgeof the strands 5, 6. The operators transmitter 3 1 is included in serieswith an impedance coil 35 and the battery 21. The secondary winding ofinduction coil 33 and condenser 36 are included with the transmitter 34in a local talking circuit. Test relay 29 is provided with a normallyopen contact 37 which is adapted to short-circuit the condenser 36 fortest purposes.

At the calling end of the link-circuit, where the novel ringing circuitsare located, I provide the usual sleeve supervisory relay 38 included ina branch between the sleeve side of the link-circuit and the live poleof the battery 21, and the usual tip supervisory relay 39 included incircuit between the strand 5 and the opposite, or grounded,pole of thebattery 21. I also provide a control relay 40, whose circuit is adaptedto be controlled by a second relay 41, included in a bridge between thestrands 5 and 6 of the link-circuit, the bridge including also contactsof the ringing device K and a suitable source of ringing current. Therelay 41 is so constructed that it will not'respond to alternatingcurrent, the said relay only energizing and attracting its armature whena path for direct current is closed therethrough. The relay 41 is asocalled sluggish relay momentarily holding its armature attracted afterits energizing circuit is opened. The ringing device K in the presentinstance comprises four key levers 7c, if, adapted severally to closebranches in the ringing bridge through generators G, G, G G Theseparallel branches also include commutators or interrupters I, I, I 1which intermittently interrupt the paths through the ringing generatorsand substitute in the bridge a direct current source, such as the directcurrent generator D. The generators G, G, G G supply alternating currentto difierent frequencies, and the call-bells 16 at the difi'erentsubstations on each line are tuned so as to respond, one to eachfrequency; Thus, for example, if the generator G is connected to line,the call-bell at substation B, and that only, will respond, while thecall-bells at stations B, B B will respond to currents from generatorsGr, G G respectively. The key levers 7s, 7c, M, 76 are adapted to bemoved so as to close ringing contacts a, e, 0 0 so as to connectgenerators G, G, G G respectively, in circuit, the branch beyond thegenerators being closed by a common contact 42. A contact 43 is alsoprovided to control a locking relay 4-4 which, when energized, rocks thelocking bar 45 about its pivots 46, so as to remove the stops .9, s, 8 sfrom their normal positions, in which they pre vent movement of the keylevers 7c, is, 76 Z0 respectively. A spring 47 restores the locking barand associated stops to their normal positions upon the deenergizationof magnet 44. A sliding bar 48, passing through guides 49, actuates thecontacts 42, 43 in response to the movement of any of the key levers 7c,70, 70 76 This action is brought about through the agency of pins 50,which engage these levers. The spring contact 42 is of sufiicientstrength to restore the bar 48 to its normal position, when it isrelieved of the pressure of the actuated levers.

If it be assumed that a party at substation A desires to converse with aparty at substation B, then the line lamp 22 of the calling line isilluminated in the usual way by the energization of line relay 20, thecircuit being completed out over the line through the induction coil 18,through switch-hook 15 and transmitter 13 of substation A and back toground at the eX- change. The operator answers the call in the usual wayby inserting the answering plug into the answering jack of the callingline, thereby closing the circuit for the sleeve supervisory relay 23and the cut-off relay 19, through the sleeve contacts of the answeringplug and jack. The energization of the cut-ofi relay disconnects theline relay 20 and puts out the line lamp 22 and at the same time extendsthe limbs of the calling line to the link-circuit strands. Theenergization of cut-oil relay 19 also provides a path in parallel withthe cut-ofl relay through the substation and the tip supervisory relay24, thereby preventing illumination of the answering supervisory lamp25. Upon depressing her listening key levers 26, 28, the operatorobtains the order from the calling party and tests the adja centmultiple ack of the called-for line, extending to station 13. If theline be busy, there'will be a potential upon the sleeve contact 4 of thejacks of that'line by reason of the connection of one of them to thesleeve contact 10 of some other link-circuit, and accordingly thetouching of tip contact 9 to such jack for the purpose of testing willcause a flow of current via conductor 30, through test relay 29, whichwill produce a click in the operators receiver to advise her of suchbusy condition. If the line be idle, there will be no such indicationand she will insert the calling plug into the tested jack of thecalledline. Upon this insertion, the sleeve supervisory relay 38 and thecut-off relay 19 will be energized over a local circuit through thesleeve contacts of the plug and ack.

The energization of cut-oft relay 19 will extend its line limbs to thejack terminals and disconnect the line relay. The energization of relay88 by its contact 51 will disconnect the test relay 29 from the tipcontact 9 and complete the strand 5 from that contact to the contacts ofcontrol relay 40. On the other hand, the energization of relay 38 willmove contact 52 to its alternate position and thereby complete a circuitfor the calling supervisory lamp 553 which, as usual, is included in abranch extending through a normally closed contact of the tip relay 39.The closing of this ground at contact 52 of relay 38 will also energizelocking relay 44 over a circuit including normal contact 43, therebyremoving the normal obstructions to the operation of the key levers 7a,7a, 0 70". Thus we see that these key levers cannot be operated untilthe link-circuit has been connected to the called line. The next act onthe part of the operator is to depress the appropriate key lever toapply that generator current which is to actuate the call-bell of thedesired substation. In the present instance, we may assume that thislever is the lever and that the proper current for ringing the call-bellat station B will be derived from generator G. Upon throwing the upperend of keyv lever 70 to the right, ringing contacts 0 and 42 are closedso as to include interrupter I and generator G in bridge of the strands.This ringing bridge, which in cludes the interrupter I and generator Gr,connects with the strands 5 and 6 at the normally closed contacts 54, 55of control relay 40. It will be apparent that if any of the other keylevers had been operated, a like bridge would have been completedthrough the corresponding generator. As the interrupter I rotates, thisbridge through the ringing generator is intermittently closed andcurrent of the proper frequency to ring the call-bell at station B isapplied to the called line. During the interval when the interrupter Ibreaks the bridge through the generator G, it provides an alternativebridging path through the direct current source D. This bridgeterminates on the one hand, as before, in the normally closed contact 54of control relay 40, and on the other hand in the ground connection fromgenerator D to the ground connection of the cutofl relay of the calledline and the ground connection of battery 21, it being noted that thepolarity of the generator D and the battery are such as to produce acumulative efiiect when thus connected in bridge. The ringing circuit,when completely traced, extends from the lower pole of generator Gr,through closed contact 42, normal contact 55, sleeve plug and jackcontacts, line limb 1, condenser 17 and call-bell 16 at the substation,line limb 2, jack and plug tip contacts, alternate contact 51, normalcontact 54, relay 41, closed contact 0, and interrupter I to theopposite pole of generator G. During the non-ringing interval, there isno circuit for direct current until the called party responds. Themovement of key lever is, in addition to closing the ringing contacts,interrupted the energizing circuit of locking magnet 44 and allowed thelocking bar 45 to return to its normal position, so that stop s, nowengaging the right hand of the lower end of the lever is, holds theringing contacts in their actuated position. Thus ringing current isapplied intermittently to the called line. As soon as the called partyresponds by removing his receiver from its hook, a circuit for directcurrent extends from the live pole of grounded generator'D, throughinterrupter I, closed contact 0, relay 41, normal contact 54, alternatecontact 51, plug and jack tip contacts, line limb 2, transmitter 13,switch-hook 15, coil 18, limb 1, andto ground by two paths, one throughthe cutoff relay 19, and the other through jack and plug sleevecontacts, sleeve supervisory relay 38, and battery 21. The closing ofthis circuit energizes the relay 41 and thereby completes a circuit forcontrol relay 40 which looks itself up through its own contact 56 andcontact 52 of relay 38. The voltage of the generator D and battery 21may be so proportioned that when the called subscriber removes hisreceiver from its switch-hook the cut-01f relay will be retainedenergized, although a momentary dropping off of its armature will notinterfere with the proper operation of the relays 41 and 40. Theoperation of the control relay disconnects the ringing bridge atcontacts 54, 55, and joins the normally disconnected sections of strands5 and 6. The completion of strand 5 results in the operation of the tipsupervisory relay 39 by current flowing over a path extending from thelive pole of battery 21, through sleeve supervisory relay 38, over thesleeve side ofthe circuit, through the transmitter at the substation andback over the tip side of the circuit through the tip supervisory relay.The energization of the latter extinguishes the calling supervisory lamp53 and closes a circuit for locking magnet 44 which extends from thelive pole of battery 21, through magnet 44, alternate contact 43,alternate contact of the tip supervisory relay 39 and alternate contact52 of the sleeve supervisory relay 38. Magnet 44 is thereby energized toremove stop 8 from its engagement with the right hand side of lever is,and thereby allow the latter and the bar 48 to be restored to'normalunder the tension of return spring 42. This movement of bar 48 restorescontact 43 to its normal position and thereby interrupts the circuit ofmagnet 44 just completed, and accordingly locking bar 45 returns to itsnormal locking position. At the end of conversation, the restoration ofthe parties receivers to their hooks causes the illumination ofsupervisory lamps 25 and 53, by reason of the deenergization of the tipsupervisory relays 24 and 39, and the operator takes down theconnection.

In carrying out my invent-ion, it will be obvious that many alterationsand modifications may be made in the structure of the apparatus andarrangement of the circuits without departing from the-spirit and scopeof the invention.

It will also be apparent that the circuit-s I have herein illustratedmay be as well applied to a trunking circuit; in contra-distinction tothe cord-circuit illustrated. The ringing contracts of the keys is, is,Z0 lcflmay also be actuated by other means. Likewise, many changes maybe made in the circuits without altering the functions of the system andwithout departing from the spirit of the invention. I therefore do not.wish to be limited to the specificmatter shown, but

aim to cover such alterations and modifications by the terms of theappended claims.

What I claim as new and desire to secure by Letters Patent of the UnitedStates is 1. A telephone system comprising a telephone line, alink-circuit for establishing connection With said line, a ringingcurrent source, contacts for connecting said source to said line totransmit ringing current thereover, means normally operative to holdsaid contacts against operation, electromagnetic means for freeing saidcontacts in response to the connection of said link-circuit to saidline, and circuit connections effective upon a subsequent operation ofsaid contacts to cause said electromagnetic freeing means to lock saidcontacts in their actuated position.

2. A telephone system comprising a telephone line, a link-circuit forestablishing connection to said line,aringing current source, contactsfor connecting said source to said line to transmit ringing currentthereover, a stop for preventing the operation of said contacts, anelectromagnet for removing said stop from its preventing position,circuit connections and a source of current for operating said magnet toremove said stop in response to the connection of said linkcircuit tosaid line, and circuit connections effective upon a subsequent operationof said contacts to cause said magnet to lock said contacts in theiractuated position.

3. A telephone system comprising a telephone line, a link-circuit forestablishing connection to said line, a ringing current source, aringing key for connecting said source to said line to transmit ringingcur rent thereover, a stop normally lying in the path of movement ofsaid key to prevent its operation, an electromagnet for removing saidstop from its normal position to permit the operation of said key,circuit connections and a source of current for operating said magnetupon the connection of said link-circuit and line, and circuitconnections effective upon a subsequent operation of said contacts tocause said magnet to lock said contacts in their actuated position.

4. A telephone system comprising a telephone line, a link-circuit forestablishing connection to said line, a ringing current source, contactsto connect said source to said line to transmit ringing currentthereover, means normally operative to hold said contact-s againstoperation, electromagnetic means for freeing said cont-acts by closing acircuit over a portion of the connected link-circuit and line, andcircuit connections effective upon a subsequent operation of saidcontacts to cause said electromagnetic freeing means to lock saidcontacts in their act-uated position.

5. A telephone system comprising a telephone line, a link-circuit forestablishing connection to said line, aringing current source, contactsto connect said source to said line to transmit ringing currentthereover, a stop normally operating to prevent the operation of saidcontacts, electromagnetic means for removing said stop from its normalposition in response to the connection of said link-circuit and line,and means responsive to the subsequent operation of said contacts tocause said electromagnetic means to again operate said stop to lock saidcontacts in their actuated position.

6. A telephone system comprising a telephone line, a link-circuit forestablishing connection to said line, a source of ringing current, a keyfor applying current from said source to said line, means for preventingthe operation of said key until said link-circuit is connected to saidline and circuit connect-ions effective upon a subsequent operation ofthe key whereby said key is locked in its actuated position.

7. A telephone system comprising a tele phone line, a link-circuit forestablishing connection to said line, a source of ringing current,normally locked ringing contacts for applying current from said sourceto said line, electromagnetic means operated upon the connection of saidlink-circuit to said line to unlock said contacts, circuit connectionseffective responsive to the subsequent operation of said contactswhereby said electromagnetic means are actuated to lock said contacts intheir actuated position.

8. A telephone system comprising a tele phone line, a link-circuit forestablishing connection to said line, a source of ringing current,normally locked ringing contacts for applying current from said sourceto said line, electromagnetic means for unlocking said contacts bycompleting a circuit over a portion of the connected link-circuit andline, and circuit connections whereby said electromagnetic means areresponsive to the subsequent operation of said contacts to lock saidcontacts in their actuated position.

9. A telephone system comprising a telephone line, a link-circuit forestablishing connect-ion to said line, a ringing current source,contacts to connect said source to said line to transmit ringing currentthereover, a stop normally operating to prevent the operation of saidcontacts, electromag netic means for removing said stop from its normalposition, means for actuating said electromagnetic means by closing acircuit over a portion of the connected link-circuit and line, and meansresponsive to the subse quent operation of said contacts to againopcrate said electromagnetic means to cause said stop to lock saidcontacts in their actuated position.

10. A telephone system comprising a called telephone line, alink-circuitfor connecting to said line, a source of ringing current, normallylocked ringing contacts for applying said source to the connected line,means dependent upon the connection of said link-circuit to said line tofree said ringing contacts, circuit connections effective upon thesubsequent operation of said contacts whereby said contacts are lockedin their actuated position, and means dependent upon the response of thecalled party to again free said contacts.

11. A telephone system comprising a called telephone line, alink-circuit for connecting to said line, a source of ringing current,ringing contacts for applying current from said source to said line,locking mechanism normally preventing the operation of said contacts, anelectromagnet for controlling said mechanism, a circuit clependent uponthe connection of said linkcircuit and line, for causing said magnet tofree said contacts, means actuated by'the subsequent operation of saidcontacts to operate said magnet to lock said contacts in their actuatedposition, and means depend ent upon the response of the called party toagain operate said magnet to free said contacts.

12. A telephone system comprising a called telephone line, alink-circuit for connecting to said line, a source of ringing current,contacts for applying current from said source to said line, lockingmechanism normally preventing the operation of said contacts, a controlmagnet for said mechanism, means dependent upon the connection of saidlink-circuit and line, to energize said magnet to free said contacts,means for interrupting said circuit upon the subsequent operation ofsaid contacts to lock said contacts in their actuated position, andmeans actuated upon the response of the called party to againmomentarily energize said magnet to free said contacts.

13. In a telephone system, a connected link-circuit and telephone line,a source of ringing current, ringing contacts for applying current fromsaid source to said line, locking mechanism for said contacts, a magnetenergized to hold said mechanism out of locking position, and means forinterrupting the circuit of said magnet upon the actuation of saidcontacts, whereby said con tacts are locked in their actuated position.

14. In a telephone system, a connected link-circuit and telephone line,a source of ringing current, ringing contacts for applying current fromsaid source to said line, locking mechanism for said contacts, a magnetenergized to hold said mechanism out of locking posit-ion, means forinterrupting the circuit of said magnet upon the actuation of saidcontacts, whereby said contacts are locked in their actuated position,and means for freeing said contacts upon the response of the calledparty.

15. A telephone system comprising a telephone line, a connectionterminal for said line having a plurality of contacts, a linkcircuithaving two terminal contactsand two onlyfor cooperatively engaging saidconnection terminal, a source of ringing current, ringing contacts forapplying current from said source to said line, locking mechanism forsaid contacts, a magnet energized upon the connection of saidlink-circuit and line, to hold said mechanism out of locking position,and means for interrupting the circuit of said magnet upon the actuationof said contacts, whereby said contacts are locked in their actuatedposition.

16. A telephone exchange system comprising a link-circuit at theexchange, a called telephone line, connection terminals for connectingsaid link-circuit and line, a.

control relay, a manually operated ringingkey, a source of ringingcurrent connected to the link-circuit strands through normally opencontacts of said key and normally closed contacts of said relay, and asecond relay multiply connected to a link circuit strand for energizingsaid relay to cut off said ringing source upon the response of thecalled party. I

17. A telephone exchange system comprising a link-circuit at theexchange, a telephone line extending to a called station, connectionterminals for uniting said linkcircuit and line, a manually operatedringing key, a control relay, ringing connections extending fromopposite sides of said linkcircuit through normally open contacts ofsaid key and normally closed contacts of said relay, a source of ringingcurrent, a source of direct current, a commutator for alternatelyconnecting said sources through said ringing connections to said line, acallbell in a normally closed path for ringing current at the calledstation, a normally open switch in a path for direct current at saidstation, a relay in said ringing circuit responsive only to currentflowing through the direct current path at said station, and a circuitclosed by said relay to operate said control relay to interrupt saidringing connections.

18. A telephone exchange system comprisinga link-circuit at theexchange, a telephone line extending to a called station, connectionterminals for uniting said link-circuit and line, a call-bell and switchat said station, a control relay through normally open contacts of whichthe link-circuit strands extend, ringing connections extending throughnormally closed contacts of said relay, a ringing current source, amanually operated key having ringing contacts for connecting said sourcethrough said connections to said line to actuate said call-bell,

and a relay and circuit connections for energizing said control relayupon the closing of said switch at said station, whereby the ringingcurrent source is disconnected and the sections of the link-circuitstrands united.

19. A telephone system comprising a i telephone line, a link-circuit, amanually operated key for applying ringing current to the line whenconnected to said link-circuit, a control relay having normally opencont acts through which said link-circuit strands extend, a secondrelay, a control circuit therefor connected as a branch of a talkingstrand of said link circuit, a switch for con ductively uniting thetelephone line limbs to operate said second relay, and means actuated bysaid second relay to operate said control relay to unite the normallydisconnected link-circuit strands.

20. A telephone system comprising a telephone line, a two-conductorlink-circuit said two conductors being talking strands, a source ofringing current, connections with said source, a control relay havingnormally open contacts through which said talking strands extend andnormally closed contacts through which said ringing connections extend,a relay connected in a branch conductor of a talking strand of the cordcircuit and operated upon the response of the called party to actuatesaid control relay to disconnect said ringing current source and tounite the normally disconnected talking strands, and means forsubsequently holding conversation over the connected link-circuit andline.

21. A telephone system comprising a two limb telephone line, a connectedlink-circuit having two talking strands, a control relay having normallyopen contacts through which said strands extend, sources of ringing anddirect current, means for connecting said sources alternately in bridgeof said line through normally closed contacts of said control relay, asecond relay included in said bridge operative only upon a flow ofcurrent from said direct current source, a switch for conductivelyuniting the line limbs to cause such a flow, and means re sponsive tothe energization of said second relay to actuate said control relay tointerrupt said bridges and complete the normally discontinuous talkingstrands, said actuation also deenergizing said second relay.

In witness whereof, I hereunto subscribe my name this 15th day of M011,1909.

HARRY G. WEBSTER.

Witnesses:

J. G. KELLOGG, CAROLYN WEBER.

Copies of this patent may be obtained for five cents each, by addressingthe Commissioner of Patents. Washington, D. C.

